BMI is far from ideal for the tall, the short or for athletes. If your friend falls into one of these suggest he checks his: Waist to hip, or Waist to Height ratios, as these have been shown to be better indicator of potential health problems than a BMI figure, as they scale / take account of muscle.
If you're after a weight or weight range, then there are numerous other formula that claim to offer a better / alternative metric, give a couple a go and if they similarly indicate you've eaten too many pies, they're probably correct:
- NewBMI
- ABSI
- BAI
- BMAI
- CI
- PI
- Ideal Range (Met Life)
- Ideal Range (Broca)
- Ideal Weight (Bornhardt)
- Ideal Weight (Devine)
- Ideal Weight (Halls)
- Ideal Weight (Hamwi)
- Ideal Weight (Lemmens)
- Ideal Weight (Lorentz)
- Ideal Weight (Miller)
- Ideal Weight (Monnerot & Dunaine)
- Ideal Weight (Peck)
- Ideal Weight (Pendle)
- Ideal Weight (Perrault & Creff)
- Ideal Weight (Robinson)
There are websites and app's that will do the calculations for you.
Similarly an estimate of your body fat may validate the above weights and indices, see: How to calculate Body Fat %.
Personally I use the BioMetrIcs app, to do both.